The catalytic effects of La0.3Sr0.7Fe0.7Cu0.2Mo0.1O3 perovskite and its hollow fibre membrane for air separation and methane conversion reactions

Abstract

Perovskite membranes have the potentials to be applied in a novel cost-effective technology for air separation or gas reactions. For this purpose, a cobalt free ceramic perovskite of La0.3Sr0.7Fe0.7Cu0.2Mo0.1O3 (LSFCM) with homogeneous composition was synthesized via the low temperature combustion process. LSFCM perovskite hollow fibre membranes were fabricated by the phase inversion/sintering technique using the prepared ceramic powder. The stability and the catalytic activity of the LSFCM ceramic powder and the prepared membrane reactor for the partial oxidation of methane into syngas were investigated. The oxygen permeation properties of the LSFCM membranes were also studied under the sweep gas mode. Under the oxygen concentration gradient created by air/sweep gas, the detected oxygen flux was 2.31 mL/min/cm2 at 1000 °C with sweep gas rate of 40 mL/min.The experimental results indicate that the LSFCM ceramic powders and hollow fibre membrane exhibited good stability when exposed in inert gases like He and air, but they were not very stable for long run operation in reducing or acid gases like H2, CH4, and CO2. The LSFCM ceramic powder exhibited excellent catalytic activity in the partial oxidation of methane for syngas production with the maximum selectivities of CO and H2 both above 90%. In contrast, the prepared blank LSFCM ceramic hollow fibre membrane displayed good selectivity towards the C2 products of ethylene and ethane with best C2 yield up to 19% raising an interesting issue of the effects of catalyst geometry on its catalytic activity, which deserves further investigation.